Multimodality Imaging in Cardiac Amyloidosis: Part 2 of 2—Diagnostic Criteria and Appropriate Utilization

Publication Date: August 29, 2019
Last Updated: March 14, 2022

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Expert Consensus Recommendations for Diagnosis of Cardiac Amyloidosis

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Criteria for Diagnosis Subtype
Histological Diagnosis of Cardiac Amyloidosis: Endomyocardial Biopsy*
lL. Endomyocardial biopsy positive for cardiac amyloidods with Congo red staining with apple-green birefringence under polarized light; typing by immunohistochemistry and/or mass spectrometry at specialized centers AL, ATTR, Other subtypes
Histological Diagnosis of Cardiac Amyloidosis: Extracardiac Biopsy
l. ATTR cardiac amyloidosis is diagnosed when below criteria are met:
a. Extracardiac biopsy proven ATTR amyloidosis AND
b. Typical cardiac imaging features (as defined below)
ATTR
2. AL cardiac amyloidosis is diagnosed when below criteria are met:
a. Extracardiac biopsy-proven AL amyloidosis AND
b. Typical cardiac imaging features (as defined below) OR
c. Abnormal cardiac biomarkers: abnormal age-adjusted NT-pro BNP or abnormal troponin T/I/Hs-Troponin with all other causes for these changes excluded
AL
Clinical Diagnosis of ATTR Cardiac Amyloidosis: 99mTc-PYP, DPD, HMDP
3. ATTR cardiac amyloidosis is diagnosed when below criteria are met:
a. 99mTc-PYP, DPD, HMDP Grade 2 or 3 myocardial uptake of radiotracer AND
b. Absence of a clonal plasma cell process as assessed by serum FLCs and serum and urine immunofixation AND
c. Typical cardiac imaging features (as defined below)
ATTR
Typical Imaging Features of Cardiac Amyloidosis
Typical cardiac echo of CMR or PET features: ANY of the below imaging features with all other causes for these cardiac manifestations, including hypertension, reasonably excluded.
1. Echo
a. LV wall thickness >12 mm
b. Relative apical sparing of global LS ratio (average of apical LS/average of combined mid+basal LS >1)
c. ≥Grade2 diastolic dysfunction
ATTR/AL
2. CMR
a. LV wall thickness >ULN for sex on SSFP cine CMR
b. Global ECV >0.40
c. Diffuse LGE
d. Abnormal gadolinium kinetics typical for amyloidosis, myocardial nulling prior to blood pool nulling
ATTR/AL
3. PET: 18F-florbetapir or 18F-florbetaben PET† ‡
a. Target to background (LV myocardium to blood pool) ratio >1.5
b. Retention index >0.030 min-1
ATTR/AL

LGE, late gadolinium enhancement; LS, longitudinal strain; SSFP, steady-state free precession; ULN, upper limit of normal, per Kawel et al39 at mid-cavity level ULN for women/men were 7/9mm (long axis) and 7/8mm (short axis), respectively.
These consensus recommendations were based on moderate-quality evidence from one or more well-designed, well-executed nonrandomized studies, observational studies, registries, or meta-analyses of such studies. The PET recommendations were based on more limited data.
* Endomyocardial biopsy should be considered in cases of equivocal 99mTc-PYP, DPD, HMDP scan. When 99mTc-PYP, DPD, HMDP is positive in the context of any abnormal evaluation for serum/urine immunofixation or serum free light-chain assay, or MGUS, this should not be seen as diagnostic for ATTR cardiac amyloidosis. In these instances, referral to a specialist amyloid center for further evaluation and consideration of biopsy is recommended.
Off-label use of FDA-approved commercial products.
18F-flutemetamol not studied systematically in the heart. 11C-Pittsurgh B compound is not FDA approved and not available to sites without a cyclotron in proximity
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Overview

Title

Multimodality Imaging in Cardiac Amyloidosis: Part 2 of 2—Diagnostic Criteria and Appropriate Utilization

Authoring Organization

Society of Nuclear Medicine and Molecular Imaging